1. Field of the Invention
The present invention relates to an output stage for integrated circuits, particularly for electronic memories having a large number of outputs.
2. Discussion of the Related Art
Various stages for electronic memories are known. Unfortunately, these stages are often highly complex and occupy a wide area of silicon in the chip wherein they are integrated.
Furthermore, since known stages have the characteristic of containing inductive/capacitive phenomena (which cause noise), the need is felt to reduce the noise present at the outputs of memories and to improve the general robustness of the output stages.
Another drawback of known output stages is that there is often a crowbar current, that is to say, a current flowing through the output transistors, which are normally arranged in a push-pull configuration, during the switching on the output from logic value "1" to logic value "0".
The size of the output transistors of the push-pull stage cannot be reduced excessively in order to minimize noise, since it is necessary to meet specifications of output stage currents.
Therefore, one aim of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, which is structurally simpler than known output stages.
Within the scope of this aim, an object of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, that comprises a smaller number of transistors than known output stages.
Another object of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, that produces less noise.
Another object of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, that reduces the sum of the current pulses on the stage output.
Another object of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, that avoids the signals to the stage buffers to be modified and therefore avoids rebounds.
Another object of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, that reduces the variation in the charge and/or discharge currents on the stage output, consequently reducing inductive/capacitive phenomena on the stage output lines.
Another object of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, that reduces the noise produced by the switching of the push-pull output of the stage.
Another object is to provide an output stage that provides an uncoupling between the output stage and the internal circuits (interaction, noise propagation).
Another object of the present invention is to provide an output stage for integrated circuits, particularly for electronic memories, that is highly reliable, relatively easy to manufacture, and at competitive costs.